In briefing documents provided in advance of the Food and Drug Administration’s Arthritis Advisory Committee on July 13th, staffers found that Sandoz’ GP2015 was highly similar to Amgen’s innovator product Enbrel (etanercept), based on the study and analytical information provided by the manufacturer.

In an interesting twist, some of the studies conducted by Sandoz compared GP2015 to the European marketed version of etanercept. The FDA’s 351(k) drug evaluation requires comparison with the US marketed version of the innovator drug. This acknowledges that there may be possible, minute differences between the biologics manufactured and sold elsewhere. To bridge this gap, Sandoz conducted additional analyses to prove the similarity of the US and EU versions of Enbrel as part of their application. The FDA reviewers deemed this acceptable (which may or may not be the case with the Advisory Committee).

Sandoz’s studies for GP2015 targeted plaque psoriasis as its main indication, but it also provided scientific justification for extrapolation to the following nonstudied indications currently held by Enbrel: rheumatoid arthritis, polyarticular juvenile idiopathic arthritis, psoriatic arthritis, and ankylosing spondylitis. The reviewers characterized the data package to support extrapolation as “extensive.”

The FDA staffers concluded at least for its psoriasis indication, “The data submitted by Sandoz show that GP2015 is highly similar to US-licensed Enbrel, notwithstanding minor differences in clinically inactive components, and that there are no clinically meaningful differences between GP2015 and US-licensed Enbrel in terms of the safety, purity, and potency of the product to support the demonstration that GP2015 is biosimilar to the US-licensed Enbrel.”